The present invention relates to a transport system for flow line production, especially in the car manufacturing industry, comprising workpieces which are movable along at least two first guides between working stations in transportation direction, at least one working station being configured as a screwing and/or assembling means which particularly comprises a plurality of working tools.
Examples of such workpieces are vehicle components such as engine block, transmission or other vehicle parts that must be worked on before actual installation into the vehicle. Said workpieces are moved along at least two first guides of the transport system between associated working stations. The two first guides can be arranged both horizontally side by side and vertically one below the other. The working stations are separately arranged next to the transport system. Corresponding supply means, separate transportation systems, corresponding installations in the building, or the like are needed for the working stations.
Due to the separate arrangement and configuration of the working stations and the transport systems for the workpieces, the constructional efforts are relatively great on the one hand, which leads to an increased demand for space and also to increased costs. On the other hand, the assignment of working stations and workpiece is made difficult by the separated configuration of working stations and transport system because the transport system for the workpiece and the working stations must be aligned exactly relative to one another to assign working station and workpiece to be worked in a reproducible way relative to one another. This very alignment leads to increased installation efforts, which is also accompanied by additional costs.
It is therefore the object of the present invention to improve a transport system of the above-mentioned type such that with little constructional efforts and at reduced costs the assignment of working station and workpiece to be worked thereby is simplified and made possible in an exact and reproducible manner.
This object is achieved in a transport system where the screwing and/or assembling means is integrated into the transport system and is movable at least over a working path in parallel with the first guides in the transport system.
Thanks to the integration of the working station in the transport system, here above all screwing and/or assembling means, additional and separate guides that are separated from the transport system are not needed. Additional installations, for instance for the supply of power to the working station, are also not needed because the supplies inherent to the transport system can be resorted to in a corresponding way. No longer needed is also a corresponding difficult alignment of the working station relative to the transport system and thus to the workpiece because an alignment is directly carried out on the transport system and not by separate guides, or the like, owing to the integration of the working station in the transport system. The working station is thus movable in a much simplified way with a permanently correct alignment relative to the workpiece.
To prevent a situation where the working station represents a load on the two first guides for the workpiece, the screwing and/or assembling means can be moved along second guides in parallel to the first guides. It is here self-evident that the second guides are integrated into the transport system and are not arranged to be separated therefrom.
The assignment of the first and second guides can be simplified and improved in that the first and second guides are arranged on the same guide stands of the transport system. Depending on the arrangement of the first guides (horizontal, vertical), the second guides are arranged accordingly. When the same guide stands are used, this results, in addition, in a normally reduced number of guide stands because guide stands are not arranged separately for first and second guides in the transport system.
A simple arrangement of the guides with simultaneously simplified orientation of the guides relative to one another can be seen in that the first and second guides are arranged in pairs at opposite sides of the guide stands. The arrangement can be configured again accordingly vertically or horizontally for respectively first and second guides.
To move the working station along the transport system and especially independently of the workpiece in a simple way, first and second guides may each have assigned thereto a drive means for workpiece and screwing and/or assembling means, respectively. The drive means for the screwing and/or assembling means is especially used when after the treatment of the workpiece the working station is returned into its initial position. It is also possible that working station and workpiece are also moved during treatment of the workpiece through a corresponding synchronization of the two drive means.
Electric motors are for instance possible as drive means, the electric motors moving working station and workpiece, respectively, along the corresponding guides by means of corresponding gears, or the like. Such an electric motor may be assigned to each working station and each workpiece, respectively. However, to move a multitude of workpieces by a drive means and also a multitude of working stations by only one drive means, the corresponding drive means may be designed as a rotatable shaft which is acted upon by at least one friction wheel having an adjustable angle of inclination. A friction drive is thereby formed which upon contact of friction wheel and shaft moves workpieces and working stations, respectively, in transportation direction. The speed in the transportation direction can here be varied by changing the angle of inclination of the friction wheel. When such friction wheels are used, it is also possible in a simple way to interrupt the kinetic connection to the drive means by removing the friction wheels from the shaft.
To hold a corresponding workpiece in a simple way and to move it independently of the form and configuration thereof along the transport system, the workpiece may be detachably secured to a workpiece carrier, the friction wheels being arranged on the workpiece carrier. It is also possible to transport different workpieces with the same workpiece carrier.
To standardize, by analogy, the working station with respect to its support on the guides, the screwing and/or assembling means as the working station may comprise a working tool carrier which is movably supported on the second guides and on which the working tools are displaceably supported towards the workpiece. This creates, inter alia, the possibility that with an otherwise identical working tool carrier different working tools are used, depending on the respective requirements, and are moved with the working tool carrier along the second guides.
For reasons of space the working tool carrier and/or workpiece carrier may be substantially plate-shaped and comprise slide rails which project in the direction of the first guides and second guides, respectively, and are displaceable along said guides. For instance, if the first and second guides are each arranged vertically one above the other, a slide rail of each guide moves along an upper side of the lower guide and a further slide rail along an upper side of the upper guide.
To reduce friction between guide and slide rails to a substantial degree, guide rolls may be rotatably supported on the slide rails.
To be able to move all working tools, if possible, in synchronism and with a permanent alignment relative to one another, the working tool carrier may be provided especially at one end with a displacement means for displacing the working tools between ready position and work position. In the work position the working tools are aligned relative to the workpiece such that the latter can be worked. In the ready position the working tools can be displaced to such a degree that they present, for instance, no obstacle for the workpieces to be worked, for workers carrying out other operations, or the like.
It is also possible that the working tools are in principle arranged fixedly in their work position, a corresponding displaceable support by displacement means, or the like, being here omitted.
To obtain a simple displacement means, said means may comprise at least two transverse carriers extending above the first and second guides, along which the working tools are displaceable in a direction transverse to the transportation direction. The working tools can thereby be assigned substantially from above to the workpiece and finally moved to the workpiece for treatment.
The working tools as such can be configured in very different ways, depending on the kind of treatment for the workpiece. Examples of such working tools are drills, thread cutters, polishing means, screwdrivers, assembling devices, or the like. To be able to carry out many screwing or drilling operations in a simple way, the working tools are designed as screwdrivers with telescopically displaceable wrench heads that are displaceably supported between retracted position and operative position, as are e.g. described in DE 201 14 662.2 of the same applicant.
It should here be noted that the working tools are initially arranged in their retracted position e.g. during displacement of the working tools into the operative position and that they are only displaced by corresponding operation of the working tools into their operative position.
The displacement between retracted position and operative position can take place automatically, and after a correct assignment with respect to the workpiece the displacement into the operative position, for instance, and the subsequent treatment of the workpiece take place. The return movement into the retracted position can also take place automatically in a corresponding way after the working of the workpiece has been completed.
In a simple embodiment the working tools can be displaced manually between retracted position and operative position.
It has already been pointed out that the first and second guides may each be arranged horizontally or vertically. With a vertical arrangement, the demand for space is normally reduced.
To move the working tools in a simple way back into the retracted position after a manual displacement of the working tools into the operative position, the working tools may be acted upon by a force towards the retracted position. Actuation by a force may e.g. be carried out by a corresponding spring means or the like.
Especially with a manual assignment of the working tools relative to the workpiece in order to permit an exact alignment between the two, the working tools in their operative position may be aligned relative to the workpiece and optionally detachably fixed in said aligned position. The alignment can take place via a corresponding indexing means, and with an arrangement of the working tools in this correctly aligned position, a fixation by locking or the like can advantageously be carried out between working tools and workpiece or between working tools and workpiece carrier.
Since the assignment of working tools and workpiece takes place in flow line production, it is self-evident that the corresponding assignment and alignment of working tool and workpiece is also maintained during movement in transportation direction. This is simply carried out in that the movements of screwing and/or assembling means are synchronized. The term “synchronization” must here be interpreted such that very different types of kinetic coupling between working station and workpiece are comprised. One type of synchronization can e.g. be performed by a detachable fixation in the aligned position; see the above observations. It is also possible that working tool carrier and workpiece carrier are detachably coupled with one another as long as there is no working of the workpiece. This means, for instance, that the workpiece carrier or the working tool carrier drag along the respectively other member. Another possibility of synchronization is an electrical/electronic synchronization which is e.g. performed via the drive means, a master-slave relationship possibly existing between workpiece carrier and working station. Of course, a corresponding synchronization can also be performed mechanically in that e.g. a kinetic connection is established between screwing and/or assembling means and workpiece or workpiece carrier, respectively.
In flow line production the workpiece moves from one working station to the other one whereas the working stations are only assigned to a specific working area. To be able to work different workpieces one after the other in this area, it must be regarded as an advantage when the screwing and/or assembling means can be returned in a direction opposite to the transportation direction up to and into their initial position automatically after decoupling of workpiece and/or workpiece carrier. In this initial position a new workpiece is then supplied and worked. It is self-evident that a return movement into the initial position can also be carried out manually.
To use working stations, for instance, not only for the return movement into the initial position in the case of a drive means for essentially all working stations, screwing and/or assembling means and drive means assigned thereto may be drivingly connected especially during the return movement. During movement together with the workpiece for the treatment thereof, a corresponding decoupling from the drive means takes place and e.g. a corresponding kinetic connection is established with respect to the workpiece and workpiece carrier, respectively, or optionally also with respect to the drive means of workpiece/workpiece carrier. The kinetic connection can of course also be realized during movement in transportation direction.
To be able to operate all working tools in synchronism and manually, all working tools can be displaced at the same time and especially manually by means of a guide plate into the operative position.
To ensure the supply of the working station during its movement along the working area of the workpiece in a simple way, the screwing and/or assembling means may have assigned thereto a cable towing means.
It is self-evident that the corresponding working tools can be fed to the workpiece in different ways. One feeding possibility is in vertical direction from the top to the bottom. The working tools are arranged accordingly above or below the workpiece in their retracted position and operative position.
However, it is also possible that the working tools are supplied in horizontal direction to the workpiece. In this instance the working tools project substantially vertically from the working tool carrier and pass at least between and through the first guides. This is applicable in case of a vertical arrangement of the guides. With a horizontal arrangement of the guides a horizontal supply of the working tools can of course take place without any projection through the first guides.